Relocatable X-ray imaging system and method for inspecting commercial vehicles and cargo containers

ABSTRACT

A readily relocatable X-ray imaging system for inspecting the contents of vehicles and containers, and a method for using the same. In a preferred embodiment, the system is relatively small in size, and is used for inspecting commercial vehicles, cargo containers, and other large objects. The X-ray imaging, system comprises a substantially arch-shaped collapsible frame having an X-ray source and detectors disposed thereon. The frame is preferably collapsible via a plurality of hinges disposed thereon. A deployment means may be attached to the frame for deploying the frame into an X-ray imaging position, and for collapsing the frame into a transport position.  
     The collapsible X-ray frame may remain stationary during X-ray imaging while a vehicle or container is driven through or towed through an inspection area defined under the frame. Alternatively, the collapsible X-ray frame may be movable relative to a stationary vehicle or container during X-ray imaging.

1. FIELD OF THE INVENTION

[0001] The field of the invention generally relates to X-ray inspectionsystems used for security purposes. More particularly, the inventionrelates to a system and method for inspecting large objects such ascommercial vehicles and cargo containers.

2. BACKGROUND OF THE INVENTION

[0002] X-ray inspection systems have generally been used to inspect thecontents of automobiles, trucks, rail cars, cargo containers, and othervessels of transport. Such systems are generally set up at airports,seaports, building entrances, border crossings, and other places wherecontraband; weapons, explosives, drugs, or other illegal items arelikely to be found in transit. X-ray inspection systems are also oftenused to verify the contents of containers and vehicles, and to ensurethe accuracy of shipping manifests and the like.

[0003] X-ray inspection systems for inspecting large objects aregenerally of the “fixed-site” variety, wherein vehicles or containersare brought to the inspection site to undergo X-ray imaging. Suchsystems commonly comprise a large inspection tunnel through whichvehicles or containers are transported. The vehicles or containers aregenerally towed through the inspection tunnel, or are transportedthrough the tunnel along a large conveyor mechanism.

[0004] As a vehicle or container is transported through the inspectiontunnel, an X-ray imaging source generates an X-ray beam toward thevehicle or container. After the X-ray beam passes through, orpenetrates, the vehicle or container, a detector receives the beam andproduces an output signal representative of the vehicle or container,and of the contents located therein.

[0005] In many of these fixed site systems, a plurality of signalsrepresentative of individual segments, i.e., successive cross sectionsor “slices,” of the vehicle or container may be transmitted, then summedtogether, to represent the entire vehicle or container. The outputsignal, or signals, is then converted into a visual image of the vehicleor container, and of the contents located. therein, which is sent to amonitor or viewing screen so that the image may be viewed by aninspection system operator. The system operator may then determinewhether any improper items are located, inside the vehicle or container,and whether the vehicle or container should be detained for physicalinspection.

[0006] While fixed-site X-ray inspection systems have adequatelyperformed in their particular implementations, the need has arisen foran X-ray imaging system that is readily relocatable and/or transportableto meet the needs of a given site or event. This is especially truegiven the threat that terrorism presents throughout the world, which hasled to a greater need to inspect vehicles, containers, and other objectsthat may be carrying contraband, explosives, or other dangerous orillegal items, in a variety of settings and venues.

[0007] Current fixed-site X-ray inspection systems are not suited tomeet this need, as they are unable to accommodate areas and events thatare not located at, or do not take place near, the inspection sitesthemselves. Moreover, current fixed-site X-ray inspection systems areunable to deter a large percentage of smugglers who simply move toalternate ports of entry to avoid sites that. utilize the fixed-siteinspection systems.

[0008] In an attempt to resolve these problems, relocatable inspectionsystems have been developed that can be assembled and used at a varietyof locations to inspect large commercial vehicles and cargo containers.In use, these systems may either be stationary, similar to thefixed-site systems described above, or they may move relative to thevehicle or container to be imaged while the vehicle or container remainsstationary. In the case of moving inspection systems, existing systemsare generally very large and are commonly powered by internal combustionengines. These moving systems may also include linear optical encodersto measure deflection and to compensate for image distortion that occurswhile the large system moves over the object to be imaged.

[0009] While existing relocatable X-ray inspection systems have beensomewhat effective at inspecting vehicles and containers at multiplelocations, they have many shortcomings. Specifically, they are generallyextremely cumbersome to transport from one location to the next, andthey require lengthy disassembling and assembling procedures.Furthermore, these systems generally require powerful machinery to loadand unload their components onto and off of multiple transport trucksfor relocation. Thus, significant time and expense are required totransport and assemble existing relocatable X-ray imaging systems. As aresult, for a given site or event requiring such an inspection system,substantial notice must be given to allow for the time and preparationrequired to transport and assemble the system. This, in turn, presentssignificant logistical problems where an event requiring securityinspections occurs on short notice.

[0010] In light of the above, a need exists for an X-ray imaging systemthat is used to inspect large trucks and cargo containers, which isreadily relocatable, and flexible in terms of on-the-spotreconfiguration, such that a wide variety of site requirements may bemet in a short amount of time, and at minimal expense.

3. SUMMARY OF THE INVENTION

[0011] The present invention is generally directed to a readilyrelocatable X-ray imaging system for inspecting the contents of vehiclesand containers, and a method for deploying and using the same. In apreferred embodiment, the system is relatively small in size compared toexisting X-ray inspection systems, and is used for inspecting commercialvehicles, cargo containers, and other large objects.

[0012] In one aspect of the invention, a substantially collapsible framehaving an X-ray source and detectors disposed thereon is used forimaging commercial vehicles and large containers. The frame ispreferably collapsible via a plurality of hinges and/or slides disposedthereon.

[0013] In another aspect of the invention, a method for deploying theframe from a car-carrier type truck or trailer into an X-ray imagingposition is described. The truck or trailer preferably includes meansfor deploying the frame into the imaging position, and for collapsingthe frame into a transport position.

[0014] In another aspect of the invention, the collapsible. X-ray frameremains stationary during X-ray imaging while a vehicle or container isdriven through or towed through an inspection area defined under theframe.

[0015] In another aspect of the invention, the collapsible X-ray framemoves relative to a stationary vehicle or container during X-rayimaging. The frame may be self-propelled, self-guided movable alongvarious types of terrain via tires, and/or guided along one or morerails or tracks.

4. BRIEF DESCRIPTION OF THE DRAWINGS

[0016]FIG. 1A is a perspective view of the relocatable X-ray inspectionsystem of the current invention set up at an inspection site.

[0017]FIG. 1B is an opposite-side perspective view of the relocatableX-ray inspection system of FIG. 1A.

[0018]FIG. 2 is a front-sectional view of an X-ray inspection frameaccording to one embodiment of the current invention.

[0019]FIG. 3 is a front view of an X-ray inspection frame according to asecond embodiment of the current invention.

[0020]FIG. 4A is a front view of an X-ray inspection frame according toa third embodiment of the current invention.

[0021]FIG. 4B is a side view of the X-ray inspection frame of FIG. 4A.

[0022]FIG. 5 is a side view of the X-ray inspection frame of FIG. 2engaging a track.

[0023]FIG. 6 is a perspective view of the X-ray inspection frame of FIG.2 in a collapsed position on the bed of a delivery vehicle.

[0024]FIG. 7 is an opposite-side perspective view of the X-rayinspection frame of FIG. 6 being deployed from the delivery vehicle ontoa track.

[0025]FIG. 8 is a perspective view of the X-ray inspection system of thecurrent invention with a delivery vehicle set up as an operator cabin atthe inspection site.

[0026]FIG. 9 is a schematic showing an X-ray inspection system usinglight sensors to guide the movement of the frame of the system.

[0027]FIG. 10 is a schematic showing light sensors for use in theembodiment of FIG. 9.

5. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0028] The preferred embodiments will now be described. with referenceto the figures. To facilitate description, any numeral identifying anelement in one figure generally represents the same element when used inany other figure. The configurations shown in the figures are forillustrative purposes only, and are not intended to limit the scope ofthe invention.

A. Description of System Elements

[0029]FIGS. 1A and 1B are opposing-side perspective views of arelocatable X-ray inspection system 10. The inspection system 10 may beused for inspecting vehicles, containers, and other objects capable ofconcealing contraband, weapons, and the like. The inspection system 10is preferably used for inspecting large commercial trucks and cargocontainers, at various sites and events such as border crossings andentrances to government buildings. For ease of description, X-rayimaging of a truck 11 will be described herein, but it is to beunderstood that the inspection system 10 may also be used to inspectother vehicles, as well as containers and other objects capable ofconcealing improper items.

[0030]FIGS. 1A and 1B show the inspection system 10 set up at aninspection site having an operator cabin 13, with a raisable gate 15connected thereto, positioned at an entrance and/or exit to theinspection system 10. The operator cabin 13 preferably contains all ofthe controls necessary for a system operator to manage and oversee theX-ray inspection process. The cabin 13 preferably contains a monitor fordisplaying X-ray images of objects and materials contained within atruck 11 being inspected, controls for raising and lowering the gate 15,an intercom system for communicating with truck drivers, and othercontrols for operating the various elements of the X-ray inspectionsystem 10, as further described below.

[0031] The inspection system 10 includes a substantially arch-shapedframe 12, which is preferably made from rigid structural steel or anyother suitable sturdy material. The frame 12 may be configured as aseries of truss beams, or may have any other suitable supportconfiguration. The frame 12 is preferably configured such that it maywithstand harsh wind and weather conditions, which may arise duringinspection of trucks, such that the frame 12 will not topple over, fallapart, or drift significantly during the inspection process.

[0032] As shown in FIGS. 1 and 2, the frame 12 preferably comprises afirst leg section 14 and a second leg section 16. The first and secondleg sections 14, 16 may have feet, wheels, tires, and/or any othersupport elements located at a base portion thereof for resting on theinspection site surface, which may be the ground, a road, a parking lot,or any other substantially uniform surface, as further described below.

[0033] The first and second leg sections 14, 16 are preferably connectedto one another by a support beam section 18. The first and second legsections 14, 16 are preferably pivotally connected to the support beamsection 18, by hinges 35 or any other suitable pivoting mechanism, suchthat the frame 12 may be collapsed, as further described below.Additionally, the support beam section 18 preferably comprises twosegments that are pivotally connected to one another at a hinge 37, orother suitable pivoting mechanism, that is located substantiallyequidistant from the first and second leg sections 14, 16, such that theframe 12 may be collapsed for transport, as illustrated in FIG. 6 andfurther described below.

[0034] The area underneath the support beam section 18 and between thefirst and second leg sections 14, 16 generally represents an “inspectionarea” wherein trucks may undergo X-ray imaging. As illustrated in FIG.2, the inspection area may have a width A 13 to 15 feet, and a height B.For example, and not by way of limitation, width A may be approximately13 to 15 feet, and height B may be approximately 14 to 16 feet. In thisexample, inspection system 10 may accommodate vehicles having a width ofup to approximately twelve feet, and a height of up to approximately 14feet.

[0035] Still referring to FIG. 2, when the support beam section 18 is ina substantially horizontal imaging position, the support beam section 18may have a height X and an overall height X′. For example, and not byway of limitation, height X may be approximately 1.5 to 2.5 feet andoverall height X′ may be approximately 15.5 to 18.5 feet. When the frame12 is in the imaging position, the first and second leg sections 14, 16are preferably substantially vertical, and each leg section preferablyhas a width Y and an overall width Y′. For example, and not by way oflimitation, width Y may be approximately 1.5 to 2.5 feet, such that theframe 12 has an overall width Y′ of approximately 16 to 20 feet.

[0036] At least one of the first and second leg sections 14, 16preferably includes an X-ray source 20 disposed thereon for generatingan X-ray beam toward a truck 11 as it passes through the inspectionarea. In FIG. 2, the X-ray source 20 is shown disposed on the first legsection 14, but it is to be understood that the X-ray source 20 may bedisposed on either, or both, leg sections 14, 16. The X-ray source 20preferably generates X-ray beams toward detectors 22 disposed on thesecond leg section 16 and the support beam section 18, such that anentire truck may be imaged, as further described below.

[0037] The X-ray source 20 may be any suitable X-ray beam generator,such as a radioisotopic source, an X-ray tube, or an electron. beamaccelerator. The X-ray source 20 preferably produces X-ray beams rangingfrom 300 keV to 10 MeV. Suitable radioisotope sources include Cesium 137and Cobalt 60. X-ray tubes with accelerating potentials up to 500 keVare generally available. Electron beam accelerator sources such aslinear accelerators are generally available with energies fromapproximately 1 MeV to 10 MeV and higher.

[0038] The X-ray source 20 preferably produces a curtain or fan ofX-rays so that the truck may be imaged one cross-section or “slice” at atime as it passes through the inspection area. The individual slices maythen be summed together to produce an X-ray image of the entire vehicleand its contents. An example of an X-ray inspection system utilizing afan-shaped X-ray beam is disclosed in U.S. Pat. No. 4,366,382 toKotowski, which is herein incorporated by reference.

[0039] A suitable collimator mechanism may preferably be used to narrowand limit the projected beam into a fan of dimensional, beams necessaryto illuminate detectors 22 in the system 10, as further described below.The collimator mechanism also preferably reduces scattered radiation byreducing the total amount of X-rays emitted during truck inspection. Asa result, a reduced amount of shielding is required to protect thesystem operator and the truck drivers and passengers.

[0040] In an alternative embodiment, the X-ray beam may be collimated toa flying spot, as opposed to a fan, that moves in a line across one ormore detectors (detector configurations are further described below).Such a configuration effectively creates a line camera, which producesimages of an object in sections that may be summed together to producean image of the entire object and its contents. The X-ray beam mayalternatively be a pencil-beam, a cone-shaped beam, or any other beamsuitable for X-ray imaging. Thus, the fan-shaped beam will be describedherein by way of example only.

[0041] The radiation produced by the inspection system 10 is preferablymaintained at a relatively minimal level compared to the radiationproduced by larger fixed-site tunnel systems. This is preferred becausethe open configuration of the inspection system 10 may allow somescattered radiation to reach a system operator and/or truck passengers,which could endanger their health if the radiation produced is at highconcentrations. To further alleviate the danger caused by scatteredradiation, radiation shields (not shown in the figures) may be disposedon the first and second leg sections 14, 16 to prevent radiation fromescaping the inspection area. As a result, scattered radiation in theinspection system 10 is substantially reduced.

[0042] As noted above, detector arrays 22 are preferably disposed on orwithin the second leg section 16 and the support beam section 18 of theframe 12 for detecting X-ray beams beam after they pass through, orpenetrate, a truck 11 or other object being inspected. By placingdetectors 22 on both the second leg section 16 and the support beamsection 18, an entire truck 11 and its contents may be imaged by theinspection system 10, as illustrated in FIGS. 1A and 1B.

[0043] Each detector array preferably comprises a linear array ofdetectors, such as photodiodes, which absorb the X-ray beams transmittedthrough the truck 11 being inspected, and convert the absorbed X-raybeams into radiographic signals representative of the truck 11 and ofmaterials contained therein. Alternatively, area detectors, such asscintillating strips or other suitable detectors, may be used to detectthe X-ray beams that pass through the truck 11, and to convert the beamsinto representative radiographic signals.

[0044] The signals produced by the detectors may preferably be sent toa. suitable image producing mechanism, such as a system processor, viacables, wires, or other suitable means. Alternatively, the imageproducing mechanism may receive the detector signals remotely, such thatno wires or cables are required. The image producing mechanismpreferably converts the detector signals into visual images of the truck11 and of materials contained therein, which may be viewed on a monitor(or other viewing mechanism) by the system operator.

[0045] In a preferred embodiment, the X-ray inspection system 10 isequipped with dual energy imaging capabilities. Dual energy imaging is aprocess wherein X-ray beams are produced by an X-ray source at multipleradiation energy levels to identify and distinguish between differenttypes of matter. A first detector element is preferably positionedopposite the X-ray source to receive and respond predominantly to X-raybeams in the lower energy range, while the remaining X-ray beams, beinggenerally of higher energy, pass through the first detector element. Asecond detector element is preferably positioned to receive and respondto the higher energy radiation passing through the first detectorelement.

[0046] A filter element may be interposed between the detector elementsto enhance discrimination in the energy response of the respectivedetector elements. The different detector elements preferably produceseparate and simultaneous signals representing patterns of relativelylower and higher energy emergent from a vehicle. Digital data processingand conversion equipment may then use these signals to producedistinctive digital information representative of each of the imagesinside the vehicle.

[0047] For example, color-encoded images may be produced whereinorganic, inorganic, and metallic materials located inside a vehicleappear as different colors on a video monitor, such that a systemoperator may readily distinguish these materials from one another. Thus,by utilizing dual energy imaging in the inspection system 10, the systemoperator may more easily identify improper materials located inside thevehicle. Dual energy imaging may be particularly effective in theinspection system 10 due to the reduced amount of scattered radiationproduced, which may otherwise interfere with optimal dual energy imagingperformance.

[0048] As an alternative, multiple radiation sources, such as two X-raysources or isotope sources may be mounted to one of the leg sections.Referring to FIG. 2, the first source 20 may be positioned as shown onleg section 14. In addition, a second radion source may be positioned onframe 12 at another location, such as near the pivot point 35. In thisembodiment, a reduced detector array may be used. For example, and againreferring to FIG. 2, only the detectors 22 on leg section 16 may beused. This embodiment may provide for the acquisition oftime-interleaved images.

[0049] The base portion of each of the first and second leg sections 14,16 may be equipped with feet, wheels, and/or tires, or any other elementsuitable for providing support and/or motion to the frame 12. The typeof element attached to the base portion of each leg section 14, 16preferably facilitates the method of X-ray inspection being implementedat a given site or event.

[0050] When an imaging method is employed in which the frame 12 remainsstationary during X-ray inspection of a moving object, feet 24 arepreferably provided at the base portion of each of the first and secondleg sections 14, 16, as illustrated in FIG. 3. The feet 24 providesupport to the frame 12, and preferably substantially prevent the frame12 from sliding or moving along the inspection site surface during X-rayinspection. The feet 24 may be circular, or any other suitable shape,and are preferably made of rubber or any other material thatsubstantially prevents sliding motion of the frame 12 along the sitesurface. The feet 24 are preferably detachably connected to the frame 12via bolts, screws, or any other suitable fastening means. Alternatively,an upper portion of each of the feet 24 may be provided with threads,such that the feet 24 may be screwed into corresponding threadedopenings in the first and second leg sections 14, 16.

[0051]FIGS. 4A and 4B illustrated preferred embodiment of the frame 12wherein the frame 12 may move relative to the object being inspected.One or more wheels 26, which preferably have tires 28 disposed thereonmay be rotatably connected to the base portion of each of the first andsecond leg sections 14, 16. Each leg section preferably has two or morewheels 26 connected thereto to provide balance and symmetry to the frame12. The wheels 26 are further preferably pivotally attached to the firstand second leg sections 14, 16 such that the wheels may pivot to steerthe frame 12 during imaging of a stationary object, as further describedbelow.

[0052] The tires 28 are preferably made of rubber, or any other suitablematerial that provides substantially uniform rolling movement to theframe 12 along the site surface. In an alternative embodiment,caterpillar style tracks may be disposed at the base portions of thefirst and second leg sections 14, 16 to provide rolling movement to theframe 12. Caterpillar style tracks may be particularly effective whenthe frame 12 performs X-ray inspection on rough or uneven surfaces.

[0053] A laser guidance system, or other suitable guidance mechanism,may preferably be used to direct the frame 12 during imaging of anobject, as further described below. The laser guidance system maypreferably include a suitable laser beam emitter that may be placed onthe ground, or at any other suitable location at the inspection site. Atarget may preferably be positioned- at a location where a systemoperator may aim the laser beam to ensure that the beam is properlyaligned, such that the frame 12 may travel toward and away from the beamalong a dimension of an object to be imaged, as further described below.The laser guidance system may also include one or more reflectors, whichmay be positioned to reflect the laser beam toward the frame 12.

[0054] The frame 12, in turn, preferably includes one or more sensorsfor recognizing the laser beam and for producing an output signalindicative of the frame's position or the direction in which the frame12 is traveling at any given moment. A processor, which may be disposedwithin the frame 12, in the operator cabin 13, or at any other suitablelocation, preferably receives the output signal from the frame sensors.The processor may then determine adjustments that must be made to thesteering of the frame 12 to ensure that the frame 12 is properlydirected along a dimension of an object to be imaged, as furtherdescribed below.

[0055]FIGS. 2 and 5 illustrate an alternative embodiment wherein thebase portion of the second leg section 16 of the frame 12 is equippedwith one or more wheels, such as v-wheels 30, which are configured toengage a rail or a track 32. The first leg section 14 may also beequipped with v-wheels for engaging a second track, or may be equippedwith one or more conventional wheels 34 for rolling along the inspectionsite surface, as illustrated. The conventional wheels 34 may have tiresdisposed thereon, or may be made of a hard plastic, or other suitablematerial, for rolling along the inspection site surface.

[0056] The track 32 is preferably secured to the inspection site surfacevia wickets, stakes, pins, or any other suitable fastening means. Thetrack may be delivered via the delivery vehicle 40, or may be deliveredby a separate vehicle and installed before the frame 12 arrives at thesite. Alternatively, the track may be permanently fixed at the site andsystem 10 may be deployed at that location.

[0057] The track 32 may preferably be made of aluminum, or any othermaterial suitable for supporting the frame 12. The v-wheels 30, in turn,may also be made of aluminum, or any other material suitable for rollingalong the track 32. During imaging of a truck 11, the frame 12 ispreferably guided along the track 32 such that the frame 12 passes overthe truck 11 to image the contents located therein, as further describedbelow.

[0058] In the embodiments wherein the frame is equipped with wheelsand/or tires, the frame 12 preferably includes a self-propelling drivedisposed thereon for powering and providing motion to the frame 12.There, self-propelling drive may include one or more synchronous drives,such as electric servo motors or any other suitable source for providingmotive power to the frame 12. Servo motors may be used due to thepreferred relatively small size of the frame 12, which does not requirethe power of a large combustion engine, such as those used on existingmovable inspection systems, to provide motion thereto.

[0059] The servo motors may preferably be activated remotely by controlslocated inside the operator cabin 13, and/or by controls located on theframe 12 itself. Alternatively, the servo motors may have wires orcables running to the controls in the operator cabin such that the frame12 may be controlled from within the operator cabin 13.

[0060] The servo motors preferably provide motion to the frame 12 in atleast two general directions, e.g., forward and backward along adimension of a truck to be imaged, as further described below. In theembodiment in which the frame 12 is guided along one or more tracks 32,the servo motors preferably provide motion to the frame 12 in twodirections along the track(s) 32.

[0061] The inspection system 10 may further include one or moregenerators for providing power to the various components of theinspection system 10. The generator(s) may be located in the operatorcabin 13,—or at any other suitable location at the inspection site. Thegenerator(s) are preferably electrically connected to the variouselectrical components in the system 10, such as the imaging equipmentand monitors, via wires and/or cables. The servo motors may also bepowered and/or recharged by the generator(s).

[0062] The X-ray inspection system 10 may preferably be delivered to aninspection site by a delivery vehicle 40, such as a car-carrier styletruck or a platform style tow truck, as illustrated in FIGS. 6 and 7, orby a trailer or other suitable vehicle. The delivery vehicle preferablyincludes a raisable bed section 42 to which the frame 12 may be attachedduring transport from one location to another. The raisable bed section42 preferably has a length to accommodate the height of the frame 12.For example, and not by way of limitation, the length may be from 16 to20 feet.

[0063] The bed section 42 preferably includes a first extendable armsection 44 that may be detachably connected to an upper portion of eachof the first and second leg sections 14, 16, and a second extendable armsection 46 that may be detachably connected to a lower portion of eachof the first and second leg sections 14, 16. The first and secondextendable arm sections 44, 46 are preferably detachably connected tothe first and second leg sections 14, 16 via locking levers, or anyother suitable locking mechanisms, that may preferably be locked andunlocked manually, and/or via controls located on or inside the deliveryvehicle, or at another suitable location.

[0064] As illustrated in FIG. 8, the delivery vehicle 40 may also beused as an operator cabin. In such an embodiment, the delivery vehicle40 preferably includes controls therein for operating the X-rayinspection system 10, as further described below. In this embodiment, araisable gate 48 may preferably be detachably connected to a bumper, orother suitable location, on the delivery vehicle, which the systemoperator may raise and lower via controls located inside the deliveryvehicle 40.

[0065] In the embodiment wherein the frame 12 remains stationary duringtruck inspection, a tow vehicle, or other suitable towing mechanism, maybe employed for pulling trucks through the inspection area, as furtherdescribed below. The tow vehicle may preferably include a winchmechanism having one or more cables that may be attached to the frontaxle or wheels of the truck to be inspected. Each of the cablespreferably includes a clamp, or other suitable attaching means; at afree end thereof, which may be secured to a wheel or axle, or othersuitable attachment point on the truck, so that the winch mechanism maypull the truck through the inspection area. In an alternativeembodiment, the delivery vehicle 40 may have a towing mechanism locatedthereon for towing trucks through the inspection area.

B. Description of the Deployment and Relocation Processes

[0066] The X-ray inspection system 10 is preferably readily deployableand collapsible, so as to reduce the time and effort involved in movingthe system 10 from one inspection site to another. When the deliveryvehicle 40 arrives at an inspection site, and at all times duringtransport, the frame 12 is preferably secured to the bed section 42 ofthe delivery vehicle 40 in a collapsed transport position, asillustrated in FIG. 6. In the transport position, the first and secondleg sections 14, 16 and the support beam section 18 are preferablycollapsed against one another via hinges 35, 37, such that they areoriented substantially parallel to one another. As a result, the frame12 occupies a substantially minimal amount of space on the bed section42 of the delivery vehicle 40.

[0067] Additionally or alternatively, leg sections 14, 16 may comprisetelescoping elements that may be retracted for transport and extendedfor deployment. Also, the leg sections 14, 16 may collapse themselvesvia hinges positioned along their length. As such, the leg sections 14,16 themselves may be extended from their retracted and/or collapsedposition when frame 12 is being deployed.

[0068] To deploy the X-ray frame 12 from the delivery vehicle, thevehicle driver preferably activates the first and second arm sections44, 46, via controls located inside the vehicle 40, such that the armsections 44, 46 move outwardly from the delivery vehicle 40 in twodirections. As the arm sections 44, 46 extend outwardly, the first andsecond leg sections 14, 16 of the frame 12, which are secured to the armsections 44, 46, move away from one another.

[0069] The arm sections 44, 46 continue to extend outwardly until thetwo segments of the support beam section 18 pivot and lock into animaging position wherein they are substantially linear to one another,and substantially perpendicular to the first and second leg sections 14,16. In the imaging position, the frame 12 is preferably substantiallyarch-shaped, as illustrated in FIGS. 2 and 7. The two segments of thesupport beam section 18 and the first and second leg sections 14, 16preferably lock into the imaging position via locking levers, or anyother suitable locking mechanisms.

[0070] After the frame 12 is extended into the imaging position, thevehicle driver preferably raises the bed section 42 of the vehicle 40,as illustrated in FIG. 7, via controls located on or inside the vehicle40, such that the frame 12 moves into a substantially upright position.In the embodiment wherein the first and second leg sections 14, 16include v-wheels 30 for engaging a rail or track 32, the vehicle driverpreferably aligns the bed section 42 of the vehicle 40 with the track 32such that the wheels 30 engage the track 32 as the frame 12 is raisedinto an upright position. In the other described embodiments, the frameis preferably raised until the base portions of the first and second legsections 14, 16, and/or any tires or feet attached thereto, come intocontact with the site surface.

[0071] Once the frame 12 is in a substantially upright position on thesite surface, the vehicle driver preferably detaches the frame 12 fromthe vehicle 40 by unlocking the locking levers manually or via controlslocated on or inside the vehicle. The frame then comes to rest on thesite surface in an upright position. In the embodiment where thedelivery vehicle 40 is used as an operator cabin, the driver preferablydrives the vehicle to a location from where the system operator maymanage the inspection process, such as that illustrated in FIG. 8. Ifthe delivery vehicle 40 is not used as an operator cabin, the driver maydrive the vehicle 40 away from the inspection area so that it does notinterfere with the inspection process.

[0072] The delivery vehicle and/or the vehicle driver may further deployany desired site accessories, such as awnings, signs, turnstiles,radiation shields, the operator cabin 13, and/or any other suitableitems, from the delivery vehicle 40. To accomplish this objective, acontrol cable mechanism, or other suitable deployment mechanism, may belocated on the delivery vehicle for deploying the desired accessories,or the accessories may be deployed manually. The deployment mechanismmay preferably be operated via controls located on the outside of, orinside the cab of, the delivery vehicle 40. Hydraulic lifts may also beemployed for deploying the operator cabin 13. In an alternativeembodiment; the operator cabin 13, and any other site accessories, maybe delivered by a separate vehicle having a suitable deploymentmechanism and/or hydraulic lift(s) located thereon.

[0073] After the accessories are deployed, the system operator (who maybe the delivery vehicle driver) may arrange the accessories in asuitable manner throughout the inspection site. Radiation shields, forexample, may preferably be set up around the inspection area, and/or maybe attached to the frame 12, via bolts, screws, hooks, or any othersuitable attachment means. Accessories that are too large and/or heavyto be moved manually, such as the operator cabin 13, are preferablydeployed directly from the delivery vehicle to their desired locations.

[0074] The operator may then connect any electrical cables and/or wiresleading from the monitoring equipment, which is preferably locatedinside the operator cabin 13, to the detector arrays 22 on the X-rayframe 12. The cables and/or wires are preferably used for transmittingsignals produced by the detectors to an image processor, or othersuitable image-producing mechanism, which provides a visual image of thevehicle and of contents located therein on the monitoring equipment.Alternatively, the detector array may produce output signals that arepicked up remotely by the image processor, in which case no cables orwires are required.

[0075] When the inspection system 10 is no longer required at a givensite, the components of the inspection system 10, and its accessories,may preferably be loaded onto the delivery vehicle(s) in substantiallythe opposite order in which they were deployed. The vehicle driver maypreferably back the delivery vehicle 40 up to the frame 12, and thenraise the bed section 42 into a substantially vertical position viacontrols located on or inside the vehicle 40. The locking levers on theextendable arm sections 44, 46 of the delivery vehicle 40 may then belocked onto the first and second leg sections 14, 16 of the frame,either manually or via controls located on or inside the deliveryvehicle 40.

[0076] Once the frame 12 is secured to the bed section 42 of thedelivery vehicle, the operator, which may or may not be the sameindividual as the driver, preferably lowers the bed section 42 intoa—substantially horizontal position, via controls located on or insidethe delivery vehicle 40. The driver may then unlock the lockingmechanisms at or near the hinge points 35, 37 on the frame 12, such thatthe frame 12 may be collapsed into a transport position. The extendablearms 44, 46 may then be retracted via the controls located on or insidethe vehicle, which causes the frame to fold up into the transportposition. In the transport position, as described above, the first andsecond leg sections 14, 16 and the support beam section 18 arepreferably collapsed against one another such that they are orientedsubstantially parallel to one another, as illustrated in FIG. 6.

[0077] After the frame 12 is secured to the bed section 42 of thedelivery vehicle 40 in the transport position, the control cablemechanism and/or hydraulic lift(s) may be used to load the various othersite accessories onto the delivery vehicle 40, and/or onto one or moreother vehicles. Alternatively, the accessories may be loaded onto thevehicle(s) manually by one or more vehicle drivers and/or systemoperators. Once all of the system components are loaded onto thevehicle(s), the vehicle(s) may be driven to the next inspection site, orto a storage facility where the inspection equipment may be stored.

C. Description of the Inspection Process

[0078] Once the inspection system 10 is deployed and assembled, truck,inspection may begin. To begin the inspection process, a truck is drivento the inspection site, where the truck driver preferably followsdirections pertaining to how he/she should proceed, which may be writtenon signs set up at the site, and/or given verbally by the systemoperator. An intercom system, similar to that used at a drive-throughrestaurant, may preferably be set up at the entrance to the inspectionsite to allow the system operator to communicate instructions, to thetruck driver, and to answer any questions posed by the driver.

[0079] A gate 15, as shown in FIG. 1, which the operator may raiseelectronically from inside the operator cabin 13, may be connected tothe operator cabin 13 at or near the entrance and/or exit to theinspection system 10. When the system 10 is ready to inspect a truck,i.e., when the previous truck has completed the inspection process, theoperator may raise the gate(s) 15 to allow the next truck to enter,and/or the inspected truck to exit, the inspection system 10. Thegate(s) 15 may then be lowered by the operator, or lowered automaticallyonce the truck clears the reach of the gate 15, to prevent additionaltrucks from entering the inspection system 10.

[0080] After the driver receives instructions from the operator and/orsigns posted at the inspection site, the driver preferably drives thetruck to a location near the frame 12, where the truck is preferablyaligned with the inspection area of the frame. The site surface maypreferably include markings, cones, or other suitable markers toidentify the area to which the driver should drive the truck. The truckmay then be inspected via any of the methods described below, or via anyother suitable inspection process.

[0081] When cargo containers are brought to the inspection site to beinspected, the containers are preferably unloaded from a deliveryvehicle and placed at or near the inspection area of the X-ray frame 12.The containers may be unloaded manually, by a suitable control cablemechanism, a hydraulic lift, or by any other suitable method. The X-rayframe 12 may then be used to image the containers, via any one of themethods Ascribed below, or via any other suitable inspection method. Forease of illustration, inspection of trucks will be described below, butit is to be understood that other vehicles, containers, and/or any otherobjects capable of concealing improper items may be inspected by theinspection system 10.

1. Method One—Stationary X-Ray Frame Imaging a Moving Object

[0082] In the embodiment illustrated in FIG. 3, the X-ray frame 12remains stationary while a truck moves through the inspection area ofthe frame 12 to undergo X-ray inspection. The system operator and/orsigns having directions written thereon preferably instruct the truckdriver to drive the truck to an area in front of the frame 12. Asdescribed above, the site surface may preferably to include markings,cones, or other suitable markers to identify the area to which thedriver should drive the truck. The truck may then be pulled through theinspection area by a towing mechanism, or other suitable pulling device,or may be driven through the inspection area by the driver, as furtherdescribed below.

[0083] In the embodiment where the truck is pulled through theinspection area, the truck driver preferably drives the truck to thearea indicated in front of the frame 12, then turns the truck off andexits the truck. The driver may then walk along the outside of theinspection system 10 to the opposite side of the X-ray frame 12, andawait delivery of the truck after it undergoes the inspection process,in a manner similar to that of a person having bags scanned at anairport.

[0084] To facilitate this process, the operator cabin 13 is preferablyprovided with an intercom system that allows the operator to communicateinstructions to the driver regarding where and how the driver shouldproceed. Warning signs and the like may also preferably be posted at theinspection site informing the driver of where it is safe and unsafe tostand or sit during the inspection process. A seating area may also beprovided where drivers may sit during the inspection process.

[0085] The system operator and/or other site workers may then attachclamps, or other suitable attachment devices, from the towing mechanismto the front axle, wheels, or other suitable location, on the truck. Thewinch mechanism may then be activated to tow the truck through theinspection area under the frame 12. The winch mechanism preferably turnsat a uniform velocity such that the trucks towed through the inspectionarea at a substantially constant speed, thereby minimizing/eliminatingdistortion in the X-ray imaging process.

[0086] As the truck begins to pass through the inspection area, an X-raybeam is generated from the X-ray source 20. The X-ray beam may beactivated by the operator, or may be activated automatically when thetruck reaches a predetermined location under the frame 12. The X-raybeam is preferably generated as soon as the cab section of the truckenters the inspection area, such that the cab section as well as thetrailer section may be imaged. Alternatively, the X-ray beam may begenerated after the cab section passes through the inspection area, suchthat only the trailer section undergoes X-ray inspection. In such anembodiment, the operator and/or one or more site workers may preferablyphysically inspect the cab section to determine whether any improperitems are present.

[0087] In the embodiment where the driver drives the truck through theinspection area, the X-ray beam is preferably generated after the cabsection containing the driver has completely passed through theinspection area, thereby minimizing the radiation to which the driver isexposed. The driver is preferably instructed by the system operatorand/or signs posted at the inspection site to drive the vehicle throughthe inspection area at a substantially uniform velocity, such thatdistortion in the X-ray imaging process is minimized/eliminated. Signallights, similar to conventional traffic lights or lights used at carwashes, may be included on the frame 12, to notify the driver whenhe/she should proceed through the inspection area.

[0088] In this embodiment, it is preferred that a device equipped withradar, lidar, or other suitable optical distance measuring equipment, bedisposed on the X-ray frame 12 for measuring the actual instantaneousposition and/or location of the truck as it passes through theinspection area. Such a device allows the system 10 to adjust the X-rayand imaging parameters to accommodate for the potentially non-uniformmotion of the truck, and to produce an image with minimal distortion.

[0089] Additionally, the radiation levels produced in the embodimentwhere the driver remains in the truck during the inspection process arepreferably maintained within the range of 0.05 micro-Sievert to 0.10micro-Sievert. This is roughly equivalent to the radiation that a personwould be exposed to if he/she were exposed to sunlight for approximatelyfive minutes, and is within ANSI Standard N43.17 (NCRP Report 116),which outlines safe limits of radiation exposure for humans. Thus, theharmful effects of radiation produced in the system 10 are preferablyextremely minimal, if existent at all.

[0090] In each of the stationary-frame embodiments, as well as themoving-frame embodiments described below, the X-ray beam is preferablyproduced as a curtain or fan of X-rays, as described above, so that thetruck is imaged one cross-section or slice at a time as it passesthrough the inspection area. A collimator mechanism, as described above,is preferably used to narrow and limit the projected beam into a fan ofdimensional beams to illuminate the detectors 22 on the frame 12. Thecollimator mechanism also limits scattering of the X-ray beam off of thetruck onto the detectors, which may otherwise result in a reduction ofcontrast in the X-ray images produced.

[0091] After the fan of X-ray beams passes through the truck, thedetectors receive the X-ray beams and produce output signalsrepresentative of the individual slices of the truck and of thematerials located therein. The output signals are sent to an imageprocessor, which sums the output signals together and converts them intoa visual image of the truck and of the contents contained therein. Thevisual image of the truck and its contents is then sent to a monitor, orother suitable viewing screen, for inspection by the operator.

[0092] The operator may then view the images on the monitor to determinewhether any improper items are contained within the truck. As explainedabove, dual energy imaging is preferably used to inspect the truck suchthat visual images of metallic materials, organic materials, andinorganic materials located inside the truck are readily distinguishablefrom one another on the monitor. For example, in a preferred dual energyimaging scheme, organic materials, which may be indicative ofcontraband, may appear as an orange color on the monitor. Metallicmaterials, conversely, may appear as a blue color. As a result, thesystem operator is preferably able to readily identify organic materialslocated inside the truck, which is made up of mainly metalliccomponents.

[0093] If the operator determines that one or more improper items mightbe contained within the truck, the operator may then exit the operator,cabin 13 to physically inspect the truck. Alternatively, one or moretruck inspectors may be employed to physically inspect trucks suspectedof containing improper items. After physically inspecting the truck, theoperator and/or inspectors may detain the driver and the truck if one ormore improper items are found inside the truck. If no such items arefound, the operator and/or inspectors may then inform the driver thathe/she is free to exit the inspection site, and the driver (and anypassengers) may then enter the truck and drive away from the inspectionsite.

[0094] Once the previously inspected truck exits the inspection system10, the operator may then raise the gate 15 on the operator cabin 13 toallow a new truck to enter the inspection system 10 to be inspected. Thedescribed inspection process may, then be repeated for the new truck.The entire inspection process is preferably performed in less than twominutes per truck (for trucks not suspected of containing any improperitems), more preferably in less than one minute. However, the time ofthe inspection may vary.

2. Method Two-X-Ray Frame Moving Along a Track to Image a StationaryObject

[0095] In the embodiment illustrated in FIGS. 1, 2, and 5, the X-rayframe 12 may move on one or more tracks 32 or rails along a length of atruck while the truck remains stationary. As described above, thedelivery vehicle 40 preferably raises the frame 12 such that thev-wheels 32 on the second leg section 16 engage the track(s) 32. Thesystem operator may then activate the servo motors, or otherself-propelling drives, on the frame 12 to move the frame into imagingposition. In a preferred embodiment, the frame 12 may be positionedadjacent to the operator cabin when the frame 12 is in the imagingposition.

[0096] Once the frame 12 is in the imaging position, the system operatorand/or signs having directions written thereon preferably instruct thetruck driver to drive the truck to an area in front of the frame 12. Ina preferred embodiment, the driver preferably drives the truck up to thegate 15 on the operator cabin 13, as illustrated in FIGS. 1A and 1B, andthen exits the truck so that the truck may be imaged. The driver maythen move to an area of the inspection site away from where the X-rayinspection occurs.

[0097] To facilitate this process, the operator cabin 13 is preferablyprovided with an intercom system that allows the operator to communicateinstructions to the driver regarding where and how the driver shouldproceed. Warning signs and the like may also preferably be posted at theinspection site informing the driver of where it is safe and unsafe tostand or sit during the inspection process. A seating area may also beprovided where drivers may sit during the inspection process.

[0098] Once the driver is safely out of the imaging area, the systemoperator preferably activates the servo motor(s), or otherself-propelling drive, to start the frame 12 in motion along the track32, such that the frame 12 begins to pass over the truck. Synchronousdrives, such as servo motors, are preferably used so that the speed ofthe frame 12 may be maintained at a substantially constant velocity asthe frame 12 passes over the truck, thus reducing/eliminating imagedistortion that may otherwise occur if the frame 12 velocity varies.

[0099] As the frame 12 passes over the truck, an X-ray beam is generatedfrom the X-ray source 20. The X-ray beam may be activated by theoperator, or may be activated automatically when the frame 12 reaches apredetermined location on the track 32. The X-ray beam is preferablygenerated as soon as the frame 12 reaches the cab section of the truck,such that the cab section as well as the trailer section may be imaged.Alternatively, the X-ray beam may be generated after the frame 12 passesover the cab section, such that only the trailer section undergoes X-rayinspection. In such an embodiment, the operator and/or one or more siteworkers may preferably physically inspect the cab section to determinewhether any improper items are present.

[0100] The X-ray beam is preferably produced as a curtain or fan ofX-rays and detected in the same manner as that described for thestationary-frame embodiments. Additionally, dual energy imaging ispreferably used to inspect the truck such that visual images of metallicmaterials, organic materials, and inorganic materials located inside thetruck are readily distinguishable from one another on the monitor, asdescribed above.

[0101] Once the frame 12 has passed over the, entire length of thetruck, the operator preferably deactivates the X-ray source 20, or theX-ray source 20 shuts off automatically when the frame 12 reaches apredetermined location on the track 32. The operator may then view theimages on the monitor to determine whether any improper items arecontained within the truck.

[0102] If the operator determines that one or more improper items mightbe contained within the truck, the operator and/or the truck inspectorsmay physically inspect the truck, as described above. After physicallyinspecting the truck, the operator and/or inspectors may detain thedriver and the truck if one or more improper items are found inside thetruck. If no such items are found, the, operator then raise the gate 15on the operator cabin, and the driver (and any passengers) may thenenter the truck and drive away from the inspection site.

[0103] Once the previously inspected truck exits the inspection site,the operator may activate the servo motors(s) or other synchronousdrives on the frame 12 to return the frame 12 along the track(s) 32 tothe imaging position, and a new truck may then enter the inspectionsystem 10. The described inspection process may then be repeated for thenew truck. The entire inspection process is preferably performed in lessthan two minutes per truck (for trucks not suspected of containing anyimproper items), more preferably in less than one minute. However, thetime of the inspection may vary.

[0104] Alternatively, the frame 12 need not be returned to its originalposition to perform another scan. This embodiment effectively providesbi-directional scanning or inspection. To this end, once the previouslyinspected truck exits the inspection area, another truck or othervehicle to be inspected may be positioned in the imaging area with itsdriver safely away therefrom. The system operator may then activate theservo motors, or other self-propelling driver, to start the frame 12 inmotion along track 32 in the opposite direction as the previousinspection. The vehicle may then be inspected in the manner discussedabove. This reduces throughput delay due to the frame 12 being returnedto a single starting position for each inspection. This also preferablyreduces the wear on the components of the system.

3. Method Three-Self-Guided X-Ray Frame, Moving Over a Stationary Objectto Image the Object

[0105] In the embodiment illustrated in FIGS. 4A and 4B, the frame 12preferably includes a plurality of wheels 26, which preferably, havetires 28 disposed thereon, disposed at a base portion of each of thefirst and second leg sections 14, 16, as described above. Once the frame12 is deployed from the delivery vehicle 40, as described above, theX-ray imaging process is performed in essentially the same manner asthat described above for the track-guided frame, with the exception thatthe frame is self-guided and may operate without a track.

[0106] In this embodiment, the frame 12 is preferably guided by asuitable guidance mechanism such as an RF guidance system or laserguidance system, or other suitable guidance mechanism. The followingdiscussion pertains to a preferred embodiment involving a laser guidancesystem. However, it should be noted that other types of guidance systemsmay be used and the following discussion is applicable to the use ofsuch other guidance systems.

[0107] In a preferred embodiment, the system operator or other siteworker places or secures a suitable laser beam emitter to the sitesurface, or other suitable location, and aims the beam at a targetpositioned in the general path of travel of the frame 12. The operatoror site worker may optionally position one or more reflectors atpredetermined locations at the inspection site, which may be used toreflect the laser beam toward the target and/or frame 12 during X-rayinspection.

[0108] Once a truck arrives at the inspection site, and the driver issafely out of the imaging area, as described above, the system operatorpreferably activates the laser beam, or other guidance system, and servomotor(s), or other synchronous drives, on the frame 12. The sensors onthe frame detect the laser beam and the system processor instructs theframe to follow the laser.

[0109] The guidance system may preferably be programmed with tolerancelimits within which the frame 12 preferably travels in order to achieveoptimal image quality. In this manner, the frame 12 need not travel in aperfectly straight line to produce a useable image, as long as itremains within the tolerance limits. The tolerance limits may vary, butfor example and not by way of limitation, the tolerance limits may beless than 6 inches from left to right and/or up and down, but may begreater or lesser depending on the sensitivity of the image-producingequipment. The frame 12 preferably accelerates, decelerates and travelsat a pre-determined speed that may be computer controlled or operatorcontrolled. The speed at which the frame 12 travels may vary accordingto the object being inspected or scanning equipment used in order topreferably provide usable X-ray images.

[0110] As the frame 12 passes over the truck, it is guided by the laserwhich is “tracked” by the sensors on the frame. If the frame moves inany direction up to the designated tolerance limit, the sensors inconjunction with the system processor instruct the frame 12 to moveslightly in the opposite or other corrective direction. For example, ifthe side-to-side tolerance limit is six inches, and the frame 12 movessix inches to the left during the inspection process, a sensor on theframe recognizes that the frame is “off course,” and the systemprocessor instructs the frame 1 to move slightly to the right as itprogresses over the truck. Furthermore, the speed at which the frame 12travels may be monitored and varied as desired.

[0111] To accomplish this objective, the wheels 26 are preferablypivotally attached to the first and second leg sections 14, 16 such thatthe wheels may pivot to steer the frame 12 and keep the frame 12 withinthe tolerance limits of the guidance system. Also, the wheels, tracks orother mechanism used to guide the frame 12 may be independently driven.For example, one track, wheel or other mechanism attached to one frameleg may be temporarily slowed as compared to the other wheel, track orother mechanism attached to the other frame leg such that the frame maybe steered from side to side.

[0112] As indicated above, the self-guided embodiment of the presentinvention as discussed above may be used with other guidance systems.For example, the frame 12 may alternatively be guided by a guide wirelaid on the ground in the direction of the intended travel path of theframe 12. The guide wire may be secured to the ground by any suitablemeans such as by stakes or tape. The guidewire system may provide forvarious motion paths beyond a forward/reverse direction of travel. Inanother embodiment, the frame 12 may follow a painted, or otherwisemarked, line positioned on the ground. Suitable sensor or detectors maybe positioned on the frame 12 to gauge the frame's position relative tothe line.

[0113] As a further alternative, the travel of frame 12 may becontrolled optically by a light. In this manner, the frame 12 may movetoward the light as its destination. Suitable optical sensors ordetectors, e.g., photosensors, mounted on the frame 12 may be used todetect the light. A second light may be used for the reverse direction.In other words, the frame 12 would travel in reverse towards the secondlight.

[0114] In this embodiment, the light source may be located at or near apoint towards which the frame 12 is intended to move. The sensors mayeach photosensors positioned in proximity to each other. The lightsource may be positioned such that the path of the light may be mid-waybetween the photosensors. Telescopes or other mechanisms that may focusthe light impinging on the photosensors may be used. As the frame 12travels, it may veer from a straight line or other desired path. Assuch, certain photosensors in the sensor mounted to the frame 12 may bemore illuminated than other of the photosensors in the sensor.Information reflecting the relative illumination of the photosensors maybe sent to and processed by the processor described above to cause theframe 12 to change its path of travel, e.g., to bring the frame 12 backto the original straight line or other desired path.

[0115] This may occur by the processor sending signals to the drivemechanisms on the legs 14, 16 of the frame 12 such that one of the legsis sped up or the other is slowed or a combination of both. As notedabove, legs 14, 16 may be equipped with independent driven wheels,tracks or other mechanisms. The variance between the illumination of thetwo sides' photocells may reflect how far off course the frame 12 is. Asthe variance increases, thus indicating that the frame 12 is more offcourse, the speed difference between the legs 14, 16 may be increased.

[0116] This embodiment is now further described with reference to FIGS.9 and 10. FIG. 9 is schematic wherein the frame 12, having legs 14, 16,and having left wheels 26L and right wheels 26R, includes a guidancesystem. It should be noted that the frame 12 may embody configurationsdifferent than that shown in FIG. 9 or different from the frames 12shown in the other figures discussed above. Accordingly, the guidancesystem discussed below may be used with frames having variousconfigurations.

[0117] Frame 26 may preferably move in the forward and reversedirections per the guidance system. The guidance system may includesensors 72 and 74 that may be mounted to opposite sides of the frame 12via brackets 73. Other appropriate mounting locations and mountinghardware 73 may be used. While sensors 72, 74 are shown in FIG. 9 on theright side of frame 12, sensors 72, 74 may be mounted elsewhere on theframe, such as on the left side. The guidance system may also includelight sources 76 and 78. Light sources 76, 78 may emit a laser light orsome other type of light that may be detected by sensors 72, 74.Accordingly, the reference to “light” below is not intended to belimited to some specific type of light.

[0118] Light source 76 may emit light generally along the path 80towards sensor 72. Light source 76 is preferably positioned so thatlight path 80 generally represents the desired path of forward travel offrame 12. Similarly, light source 78 may emit light generally along path82 towards sensor 74, and is preferably positioned so that light path 82generally represents the desired path of reverse travel of frame 12.Light sources 76, 78 may be mounted on a tripod or some other movablestructure (not shown) resting on the ground near the inspection sight.Alternatively, light sources 76, 78 may be mounted to an appropriatewall or other stationary structure. It is preferred that sensors 72, 74are positioned relative to each other so that the light emitted fromsources 76, 78 do not shine into each other.

[0119] Referring to FIG. 10, sensors 72, 74 are now further described.The sensor in FIG. 10 bears the reference numeral 72, but sensor 74 maybe similarly configured. As shown, sensor 72 preferably includes lens 84and photosensors 86 and 88. Lens 84 may comprise any suitable materialto accommodate the type of light being used. While two photosensors 86,88 are shown, it should be noted that some other number of photosensors,or a photosensor array, may be used.

[0120] As mentioned above, light path 80 generally represents thedesired path of travel of frame 12. If the frame 12 has been movingalong in a relatively straight line along light path 80, light path 80preferably impinges on the lens 84 at or near its mid-point 84A. This ispreferably accomplished by positioning light source 76 relative to theframe 12 and sensor 72 so that the direction of light path 80 doesrepresent the desired path of travel. So when the frame 12 is movingalong path 80 and is oriented properly, the direction of the light beamis preferably not significantly altered as it passes through lens 84 andimpinges on photosensors 86, 88.

[0121] Accordingly, the amount of light received by each of photosensors86 and 88 from light beam 80 after it passes through lens 84 ispreferably the same, about the same, or within some range of tolerance.It should be noted that while light beam 80 is shown in FIG. 10 as asingle line, light beam 80 will generally irradiate each of photosensors86 and 88 to some extent even though these photosensors may not beexactly in the path of the light beam 80. In other words, when the frame12 is generally on the correct path 80 and is oriented correctly, thelight beam 80 covers equal, about equal, or similar enough portions ofthe photosensors 86, 88.

[0122] Signals may be generated reflecting the amount of light energyreceived by each of the photosensors 86 and 88. These signals may besent to a processor (not shown in FIG. 10 but described above) forprocessing. Where the respective signals from photosensors 86, 88 showthat the amount of light that they respectively received is the same,about the same, or within a specified tolerable range, the processorneed not instruct the drive wheels 26 to alter the path of the frame 12.As such, frame 12 may continue to generally travel in the direction ofthe desired path 80.

[0123] If the frame 12 has strayed from the desired path 80, light beam80 will impinge on lens 84 at a location other than its mid-point. Forexample, if the frame has strayed to the left, beam path 80 will impingeon lens 84 at a location 84B as shown in FIG. 10. In this situation,beam path 80 actually impinges on lens 84 from a different path denotedas path 80B. As such, the direction of beam path 80B will be altered asit passes through lens 84 such that beam path 80B will more stronglyirradiate photosensor 88 than photosensor 86.

[0124] In this situation, the signals reflecting the amount of lightreceived by photosensors 86, 88 will be sufficiently different. Thesesignals may be sent to a processor which may instruct the drive wheels26 to alter the direction of frame 12 to compensate. To this end, forexample, the processor may instruct wheels 26L to speed up, wheels 26Rto slow down, or a combination of the two. As the direction of travel ofthe frame 12 is altered towards the desired path of travel 80, the lightemitted from source 76 will eventually impinge on lens 84 at about itsmidpoint 84A and both photosensors 86, 88 will be illuminated equally,about equally, or within some specified tolerance range. When thisoccurs, the signals sent to the processor will be the same, about thesame or within some specified tolerance range such that furthercompensation by the wheels 26 may cease.

[0125] If the frame 12 has strayed to the right of the desired path 80,beam path 80 will impinge on lens 84 at a location 84C as shown in FIG.10. In this situation, beam path 80 actually impinges on lens 84 from adifferent path denoted as path 80C. As such, the direction of beam path80C will be altered as it passes through lens 84 such that beam path 80Cwill more strongly irradiate photosensor 86 than photosensor 88.

[0126] In this situation, the signals reflecting the amount of lightreceived by photosensors 86, 88 will again be sufficiently different.These signals may be sent to a processor which may instruct the drivewheels 26 to alter the direction of frame 12 to compensate. To this end,for example, the processor may instruct wheels 26R to speed up, wheels26L to slow down, or a combination of the two. As the direction oftravel of the frame 12 is altered towards the desired path of travel 80,the light emitted from source 76 will eventually impinge on lens 84 atabout its midpoint 84A, and both photosensors 86, 88 will be illuminatedequally, about equally, or within some specified tolerance range. Whenthis occurs, the signals sent to the processor will be the same, aboutthe same or within some specified tolerance range such that furthercompensation by the wheels 26 may cease.

[0127] The guidance of frame 12 in a reverse direction may occur insimilar fashion. In other words, should the frame 12 proceed on thecorrect path and be oriented correctly, the light beam 82 from source 78will impinge the lens 84 at the midpoint and the frame 12 will beinstructed to continue travelling on the same course. If the frame 12strays from the desired path 82, signals may be generated reflecting thedifferent amounts of light received by photosensors 86, 88 which mayresult in the processor providing appropriate compensating instructionsto the wheels 26.

[0128] The guidance system of this embodiment may also indicate when theframe 12 has reached the end of the desired length of forward or reversetravel. To this end, the guidance system may include “end of travel”markers 90 and 92 that may be located at the ends of the desired forwardand reverse paths of travel. Markers 90, 92 may be positioned relativeto the frame 12 in similar fashion to light sources 76, 78. “End oftravel” sensors 94 and 96, which correspond to markers 90, 92respectively, are preferably mounted to frame 12 via brackets 97.

[0129] Sensors 94, 96 preferably detect the proper point for the frame12 to stop. Sensors 94, 96 may be proximity sensors that detect anobject, i.e., marker 90 or 92, such as a metal plate or a pole. In oneembodiment, the light sources 76, 78 may be mounted to markers 90, 92respectively. When sensors 94, 96 detect the end of the path of forwardor reverse travel, they may generate appropriate signals to a processorto instruct the wheels 26 to stop moving and/or move in the reversedirection.

[0130] In general, the guidance system described above may operate asfollows. The vehicle to be inspected and/or frame 12 are positionedrelative to each other and relative to the light sources 76, 78 andmarkers 90, 92. As the inspection begins and the frame 12 moves forward,the light source 76 emits light which is received by sensor 72 forappropriate signals to be generated and sent to the processor.Appropriate instructions are then sent to the drive wheels 26. After theinspection has occurred and the frame 12 has reached the end of itsdesired forward length of travel, sensor 94 sends appropriate signals tothe processor to stop the frame 12 and reverse its direction. Thereverse movement of frame 12 may then be guided by light source 78 andsensor 74 up until the time that sensor 96 detects that the end of thedesired reverse line of travel has been reached. The frame 12 may thenbe stopped, the inspected vehicle may then exit the inspection area, andanother inspection may occur.

[0131] The frame 12 is preferably maintained in a relatively stiffconfiguration such that frame deflection during X-ray inspection isreduced or eliminated, which in turn reduces or eliminates imagedistortion. To further maintain proper physical alignment, the frame 12may be equipped with strain gauges that measure strain and/or stressbuilding in the frame 12 before frame deflection actually occurs. Thestrain gauges may then act to counteract and reduce the strain and/orstress occurring in the frame 12 such that deflection of the frame doesnot occur.

[0132] The use of strain gauges provides an advantage over prior artmobile inspection systems, which generally use linear optical encodersand shaft encoders to measure and compensate for deflection after thedeflection has already occurred. Linear optical encoders and shaftencoders, or other suitable compensating equipment, may be used in theinspection system 10, however, if they are more suited to the imageproducing equipment being used.

[0133] The frame 12 may include proximity sensors or physical contactswitches to stop the frame 12 if it comes close to or in contact withanother object. Additionally, system 10 may be equipped with cutoffmechanism, e.g., “deadman” switch mechanism that may be used by theoperator to stop the frame 12. The cutoff mechanism may also beactivated automatically under computer control if certain conditionsarise.

[0134] After the frame 12 passes over the complete length of the truckbeing inspected, the X-ray source may be deactivated and the frame 12may then move in the opposite direction over the truck such that theframe 12 returns to its imaging position. The operator may then view theimage of the truck and its contents on the monitor to determine whetherany improper items might be present. The operator may then detain thetruck and the driver if improper items appear to be present, or informthe driver that he/she is free to leave the inspection site if noimproper images appear on the monitor, as described above. Once theprevious truck is cleared or detained, and moved away from theinspection area, the next truck may enter the inspection system 10 toundergo X-ray inspection.

[0135] Thus while embodiments and applications of the present inventionhave been shown and described, it would be apparent to one skilled inthe art that other modifications are possible without departing from theinventive concepts herein. The invention, therefore, is not to berestricted except in the spirit of the claims that follow.

What is claimed is:
 1. A relocatable security inspection system, comprising: a frame having first and second leg sections spaced apart from one another, the frame defining an inspection area; an X-ray source disposed on the frame for generating an X-ray beam into the inspection area toward the object; a detector disposed on the frame distally from the X-ray source for receiving the X-ray beam after the X-ray beam passes through the object, and for producing an output signal representative of the object and contents thereof; an image processor for converting the output signal into a visual image of the object and contents thereof;
 2. The system of claim 1 wherein the frame is movable along a dimension of the object.
 3. The system of claim 2 further comprising a self-propelling drive attached to the frame for moving the frame.
 4. The system of claim 3 wherein the self-propelling drive comprises an electric motor, the electric motor further used for regulating a speed and an alignment of the frame during movement of the frame.
 5. The system of claim 2 further comprising a track for guiding the frame, wherein at least one of the first and second leg sections includes a wheel disposed thereon, the wheel movable along the track.
 6. The system of claim 2 further comprising a plurality of wheels disposed on the first and second leg sections for providing rolling movement to the frame.
 7. The system of claim 6 further comprising a tire disposed on each of the plurality of wheels for providing rolling movement to the frame along a surface.
 8. The system of claim 1 wherein the first and second leg sections each include a base portion configured to rest on a surface and maintain the frame in a stationary position during imaging of a moving object.
 9. The system of claim 1 further comprising a delivery vehicle for deploying the frame to an imaging position.
 10. The system of claim 1 further comprising a radiation shield attached to the frame for preventing radiation produced by the X-ray beam from escaping the inspection area.
 11. The system of claim 1 wherein the frame is collapsible.
 12. The system of claim 1 wherein the X-ray source is disposed on one of the first and second leg sections.
 13. The system of claim 1 wherein the detector is disposed on at least one of the first and second leg sections and a support section that connects the first and second leg sections.
 14. The system of claim 1 further comprising an operator cabin having controls therein for operating the frame.
 15. A relocatable security inspection system, comprising: a support beam section having a first end and a second end; a first leg section pivotally connected to the first end of the support beam section, the first leg section pivotable between an imaging position in which the support beam section and the first leg section are substantially perpendicular to one another, and a transport position in which the support beam section and the first leg section are substantially parallel to one another; a second leg section pivotally connected to the second end of the support beam section, the second leg section pivotable between an imaging position in which the support beam section and the second leg section are substantially perpendicular to one another, and a transport position in which the support beam section and the second leg section are substantially parallel to one another.
 16. The system of claim 15 wherein the support beam section comprises two sub-sections pivotally connected to one another, the two sub-sections pivotable between an imaging position in which the two sub-sections are substantially linear relative to one another, and a transport position in which the two sub-sections are substantially parallel to one another.
 17. The system of claim 15 further comprising an X-ray source disposed on one of the first and second leg sections for generating an X-ray beam toward the object to be imaged.
 18. The system of claim 17 further comprising a detector disposed on at least one of the first and second leg sections and the support beam section for receiving the X-ray beam after the X-ray beam passes through the object, and for producing an output signal representative of the object and contents thereof.
 19. The system of claim 18 further comprising means for converting the output signal into a visual image of the object and contents thereof.
 20. The system of claim 15 further comprising a self-propelling drive attached to at least one of the first and second leg sections for moving the frame. 21 The system of claim 15 further comprising a wheel disposed on at least one of the first and second leg sections for providing rolling movement of the frame.
 22. The system of claim 21 wherein the wheel is configured to roll along a track that guides the frame.
 23. The system of claim 21 further comprising a tire on the wheel to provide rolling movement to the frame along a surface.
 24. The system of claim 15 wherein the first and second leg sections each include a base portion configured to rest on a surface; and maintain the frame in a stationary position during imaging of a moving object.
 25. The system of claim 15 further comprising, a locking mechanism disposed on at least one of the support beam section and the first and second leg sections for detachably connecting the inspection system to a delivery vehicle.
 26. A method of inspecting an object, comprising the steps: deploying an X-ray imaging scanner from a delivery vehicle into an imaging position wherein an inspection area is defined by the scanner; generating an X-ray beam from the scanner into the inspection area toward an object to be imaged; detecting the X-ray beam after the X-ray beam passes through the object; producing an output signal representative of the object and contents thereof; converting the output signal into a visual image of the object and contents thereof.
 27. The method of claim 26 further comprising the step of moving the object through the inspection area while the scanner remains stationary.
 28. The method of claim 27 wherein the step of moving the object comprises towing the object through the inspection area.
 29. The method of claim 27 wherein the object is a vehicle and the step of moving the object comprises a driver driving the vehicle through the inspection area, wherein the step of generating the X-ray beam does not occur until after a section of the vehicle containing the driver has passed through the inspection area, such that the driver is not directly exposed to the X-ray beam.
 30. The method of claim 26 further comprising the step of moving the scanner relative to the object to image the object.
 31. The method of claim 30 wherein the step of moving the scanner comprises moving the scanner along a track that guides the scanner.
 32. The method of claim 30 wherein the step of moving the scanner comprises self-propelling the scanner relative to the object.
 33. The method of claim 32 further comprising the step of regulating the speed and/or alignment of the scanner with an electric motor.
 34. The method of claim 30 further comprising the step of X-ray imaging the object at a plurality of energy levels such that visual images of metallic materials, organic materials, and inorganic materials located inside the object are distinguishable from one another.
 35. A method of deploying a security inspection system from a delivery vehicle to an inspection site, the inspection system including a frame having first and second leg sections pivotally connected to opposite ends of an support beam section, comprising the steps of: activating a deployment mechanism located on the delivery vehicle; moving the frame into an X-ray imaging position via the deployment mechanism; inclining a bed section of the delivery vehicle until a base portion of at least one of the first and second leg sections comes into contact with at least one of a surface of the inspection site and an object located on the surface of the inspection site; detaching the frame from the bed section of the delivery vehicle such that the frame comes to rest in a substantially upright position on the surface of the inspection site.
 36. The method of claim 35 wherein the step of moving the frame into an X-ray imaging position comprises moving the first and second leg sections away from one another such that the support beam section pivots into a locked position in which the support beam section is substantially perpendicular to the first and second leg sections.
 37. The method of claim 35 wherein the inclining step comprises inclining the bed section until a wheel located on the base portion of at least one of the first and second leg sections engages a track secured to the surface of the inspection site.
 38. The method of claim 35 wherein the inclining step comprises inclining the bed section until a plurality of tires located on the base portions of the first and second leg sections come into contact with the surface of the inspection site.
 39. A method of deploying a security inspection system from a delivery vehicle to an inspection site, the inspection system including a frame having first and second leg sections pivotally connected to opposite ends of a support beam section, the support beam section comprising first and second scanner segments pivotally connected to one another, the method comprising the steps of: activating a deployment mechanism located on the delivery vehicle; moving the first and second leg sections away from one another via the deployment mechanism such that the support beam section pivots into an imaging position in which the first and second scanner segments are locked into place substantially linear to one another, and substantially perpendicular to the first and second leg sections; inclining a bed section of the delivery vehicle until a base portion of at least one of the first and second leg sections comes into contact with at least one of a surface of the inspection site and an object located on the surface of the inspection site; detaching the frame from the bed section of the delivery vehicle such that the frame comes to rest in a substantially upright position on the surface of the inspection site.
 40. The method of claim 39 wherein the inclining step comprises inclining the bed section until a wheel located on the base portion of at least one of the first and second leg sections engages a track secured to the surface of the inspection site.
 41. The method of claim 39 wherein the inclining step comprises inclining the bed section until a plurality of tires located on the base portions of the first and second leg sections come into contact with the surface of the inspection site.
 42. The system of claim 3 wherein the self-propelling drive further comprises: a light source that emits a light beam representing the desired path of travel of the frame, the light source being positioned to one side of the frame; a light sensor mounted to the frame and that receives light from the light source and that detects whether the frame is straying from the desired path of travel; and a processor to provide instructions to the frame to correct its path of travel based on information from the light sensor.
 43. The system of claim 42 wherein the light sensor further comprises a lens, and at least two photosensors.
 44. The system of claim 42 wherein the light source and light sensor guide the forward movement of the frame, and a second light source is positioned to the other side of the frame, and a second light sensor is mounted on the other side of the frame, said second light source and second light sensor guiding the reverse movement of the frame.
 45. The system of claim 42, further comprising: an end of travel marker positioned to one side of the frame; and a sensor mounted to the frame that senses the end of travel marker to stop the frame.
 46. The system of claim 45 wherein the sensor senses the end of travel marker to stop the forward movement of the frame, and a second end of travel marker is positioned to the other side of the frame, and a second sensor is mounted on the other side of the frame, wherein said second sensor senses the second end of travel marker to stop the reverse movement of the frame.
 47. The system of claim 11 wherein the frame is collapsible via a plurality of hinges.
 48. The system of claim 11, further comprising a delivery vehicle for deploying the frame to an imaging position, and for collapsing the frame to a transport position.
 49. The system of claim 1, the frame further comprising a support section that connects the first and second leg sections.
 50. The method of claim 26 wherein the X-ray imaging scanner is collapsible, the deploying step further comprising transforming the X-ray imaging scanner from a collapsed position to the imaging position.
 51. The method of claim 32 further comprising the step of regulating the speed and/or alignment with a light source, a light sensor and a processor.
 52. The system of claim 15 wherein the first leg section and second leg section are detachable from the support beam.
 53. The system of claim 15 wherein the first leg section and second leg section comprise telescoping members.
 54. The system of claim 15 wherein the first leg section and second leg section are collapsible via hinges located along their lengths. 